[Swan] Need 250C help

[Kenneth G. Gordon]

On 1 Jun 2007 at 19:50, Glen Zook wrote:

> The Swan 250 series is "OK" for "hunt and pounce" type
> of operation.  But, for any operation that involves
> lengthy transmissions or series of transmissions they
> do "tend" to be a bit "drifty"!  Some units are better
> than others but they all seem to drift quite a bit.
> 
> The fact that the VFO covers the entire 4 MHz of the
> band with the "band set" variable capacitor doesn't
> help with the stability at all!
> 
> It is a fault with the vast majority of Swan units (HF
> as well as 6 meters) in that instead of using a
> relatively narrow VFO (i.e. 5.0 MHz to 5.5 MHz) and
> heterodyning the frequency to various bands with
> crystal controlled oscillators Swan chose to mix the
> VFO directly with the SSB generator.  The result is
> the higher the band the higher the VFO frequency has
> to be.  The higher the VFO frequency the harder it is
> to get good stability.  Also, the harder it is to get
> decent calibration.

Yes to all of the above. However, there are several ways to improve 
stability in the Swan rigs. There have been at least three articles in the 
various ham mags over the years addressing this issue. Ham Radio 
mag had at least one.

I have a Swan 350C which I intend to work on when the opportunity 
arises.

Ken Gordon W7EKB